Broadcast has an almost century long tradition in radio. Even with TV, the history goes back to 1930's. Broadcasting has been successful throughout the world in bringing both entertainment and information to mass audiences.
The latest step in broadcasting is the digitalization of both radio and TV. Digital radio has not gained much acceptance on the market. However, many hope that digital TV will bring new benefits and services to the consumer and, as a result, generate new revenue streams for the broadcasting industry. The basic concept of the TV service itself has, however, not changed much. Rather, the TV lives on as before even if it has become digital.
In later half of 1990's we saw the boom of the Internet. A whole set of new services and content became available to the consumers during a short, revolutionary and hype intense period. That period introduced e-commerce, Internet Service Providers (ISPs), Portals, eyeballs game, dotcom companies and even the new economy. The developments in both access technologies (e.g. ADSL) and coding technologies (e.g. MPEG-4 streaming) have made it possible to bring rich media content like video content to homes via the Internet. Despite of these technology and market breakthroughs media houses have been reluctant to distribute their content via the Internet due to its “free-of-charge” nature and the direct threat of piracy. Neither has Internet been able to challenge the role of traditional media as the primary advertisement platform despite its great popularity.
Broadcast is a flexible system allowing broadcasters to choose from a variety of options to suit their various service environments. Broadly speaking the trade-off in one of service bit-rate versus signal robustness. In some cases this is solved by incorporating basically separate data transmissions into a single transmission by modulating the data in such a way that receivers with “good” reception conditions can receive both or all, while those with poorer reception conditions may only receive the one with more robust coding. A problem occurs when the receiver receives such a transmission, for example collects information on the existing signals announced. There is no distinction for such transmissions incorporated into the single transmission. On the basis of the parsed information , the receiver is only able to find the signal with more robust signal transmission. The other(s) transmission is completely unknown to the receiver. Thus, many services or parts of the transmitted services are not available, or even the worse case, they are not known at all. This has created a need to identify such transmissions.
In view of various inherent limitations of broadcasting, it would be desirable to avoid or mitigate these and other problems associated with prior art systems. Thus, there is a need for indicate a linkage between a transport stream and a hierarchical priority.